AMSTERDAM — presented at the European Academy of Dermatology and Venereology (EADV) 2024 Congress are further validated.
“We now have a pipeline of clinical studies in PN. Who would have even thought that a few years ago,” said Shawn Kwatra, MD, professor and chair, Department of Dermatology, University of Maryland School of Medicine, Baltimore. That is a remarkable turn of events for a difficult disease, he added.
Dr. Shawn G. Kwatra
Dr. Kwatra
Dupilumab, a monoclonal antibody that inhibits the activity of interleukin (IL)–4 and IL-13, was the first treatment approved for PN by the Food and Drug Administration 2 years ago. Approval of nemolizumab, a monoclonal antibody that targets IL-31, a cytokine strongly implicated in the itch response, followed in August 2024. Povorcitinib, which targets Janus kinase 1 (JAK1), is on track to be the third.
New data on both nemolizumab and povorcitinib were presented in late breaking news sessions at EADV.
For povorcitinib, a JAK inhibitor, Dr. Kwatra presented extended phase 2 results through 40 weeks at a late-breaker session at the EADV meeting. They follow 16-week data from a randomized study presented earlier this year.
Of the 146 patients followed in the original 16-week randomized trial, which compared 15, 45, and 75 mg of oral povorcitinib once daily against placebo, 126 entered an extension in which all patients were treated with active therapy. In this single-blind phase, those who were responders at 16 weeks received 45 mg povorcitinib, and those who were nonresponders received 75 mg povorcitinib.
At 16 weeks, all doses were superior to placebo in achieving at least a 4-point reduction on the Itch Numerical Rating Scale (NRS4) and the Investigator Global Assessment (IGA) score 0 or 1 (clear or almost clear), as well as in a composite endpoint of both. However, even though the lowest dose of povorcitinib was active, there was a “very clear dose response” demonstrated in speed of response and proportion of responders, according to Dr. Kwatra.
On the 75-mg dose, the time to improvement was a median of 19 days, while the median times to improvement were 35 days on the 45-mg dose and 58 days on the 15-mg dose.
Among povorcitinib responders, 96% had met the NRS4 response at the time they entered the extension study. During the extension study, the proportion of responders who maintained this level of itch control hovered around 90% for the duration. The proportion was 89% at week 40.
The proportion of responders at 16 weeks achieving IGA 0/1, signifying clear or almost clear, was 93%. Again, the rate hovered around 90% for the full 40 weeks. At week 40, the proportion at this outcome was also 89%. The composite outcome among responders persisted at about 80% for most of the follow-up but fell to 63% at the last follow-up.
Among nonresponders who transitioned to 75 mg povorcitinib for the extension period, the NSR4 response rates climbed within 4 weeks to approximately 60% and reached 70% at week 40. For the endpoint of IGA 0/1, rates rose incrementally among the nonresponders over time, reaching 51% at week 40. The composite endpoint was reached at 40 weeks by 41% of nonresponders switched to 75 mg during the 24-week extension.
The results at 40 weeks were highly encouraging, according to Dr. Kwatra, who reported there were no surprises in regard to safety during the extension period. He reported some transient reductions in hemoglobin and infections that resolved, but there were no cardiac events or other more serious events that have been previously associated with JAK inhibitors during the 40-week study period.
When asked if there might be an advantage for povorcitinib relative to the monoclonal antibodies in regard to speed of onset, Dr. Kwatra said that there are no comparative data. Like previous experience with dupilumab, some patients responded rapidly with povorcitinib, but others took longer to achieve benefit.
This variability in response is consistent with the growing evidence that PN is a heterogeneous disease, according to Dr. Kwatra. With multiple up-regulated cytokines implicated in the pathogenesis of PN, he suggested that more treatment options would be useful. When it comes to the multiple molecular pathways involved in the pathogenesis of PN, he said, “patients can be at a different edge of a spectrum.”
In other evidence suggesting that more options are needed, another late-breaking news study at the 2024 EADV congress underlined the fact that PN is a chronic disease. Presented by Franz J. Legat, MD, professor of dermatology at the Medical University of Graz, Graz, Austria, the data involved a withdrawal evaluation nested in a long-term extension (LTE) of the OLYMPIA pivotal trials with nemolizumab.
After 52 weeks in the LTE, 34 patients entered the OLYMPIA DURABILITY study, in which they were randomized to withdrawal or to continue on nemolizumab on an every 4-week dosing schedule.
The relapse rate over 24 weeks was 16.7% (3 of 18 patients) in the continuous nemolizumab arm and 75% (12 of 16 patients) in the withdrawal arm. The median time to relapse was 112.5 days for those in the withdrawal arm and was not reached during follow-up in the nemolizumab arm.
Praising the patients who were willing to risk PN relapse by entering this randomized trial, Dr. Legat said that the study shows a relatively high risk for relapse within months of treatment withdrawal even after good PN control over a period of 52 weeks.
“These data clearly support continuous nemolizumab beyond 52 weeks,” he said.
Dr. Kwatra reported financial relationships with AbbVie, Arcutis, Biotherapeutics, Aslan, Celldex, Galderma, Genzada, Johnson & Johnson, Novartis, Pfizer, Regeneron, Sanofi, and Incyte, which is developing povorcitinib for PN. Dr. Legat reported financial relationships with Almirall, Celgene, Eli Lilly, Menlo Therapeutics, Novartis, Pfizer, Trevi, Vifor, and Galderma, which provided funding for the nemolizumab studies.
A version of this article appeared on Medscape.com.